Systematics, biostratigraphy and biogeography of brachiopods and other fossils from the middle Cambrian Nelson Limestone, Antarctica

An assemblage dominated by acrotretid brachiopods (Prototreta millsi Brock and Percival, 2006) is described from the Nelson Limestone of the Transantarctic Mountains, Antarctica. The formation also includes paterinids (Micromitra sp. cf. M. nerranubawu Kruse, 1990 and Dictyonina australis Roberts and Jell, 1990), lingulids (Oepikites?haimantensis Reed, 1910) and acrothelids (Acrothele sp. cf. A. vertex Reed, 1910). The macrofauna also contains orthids (Diraphora dyunyin Kruse, 1990). The associated fauna include sponge spicules present in vast abundance. Other recognisable small shelly fossils (including chancelloriids and hyolithelminths) make up a small section of the fauna. Trilobites belong to taxa previously described from the Nelson Limestone and support the Drumian age proposed for the formation. Palaeobiogeographic analysis indicates that the brachiopod fauna corroborates previously described strong links with Australasia and also suggests a strong link to Indian material, corroborating previous evidence for an East Gondwanan faunal province in the middle Cambrian.